Calculation of Adjustment Factors for Standardizing Lactations to Mature Age and 305-Day and Estimation of Heritability and Repeatability of Standardized Milk Yield of Simmental Cattle Reared on Kazova State Farm

Authors : Süleyman ÇİLEK, Mehmet Emin TEKİN

Pages : 283-289

View : 9 | Download : 6

Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :Adjustment factors of lactation milk yield to mature age and 305-day were calculated and heritability and repeatability of milk yield were estimated for Simmental cows reared on Kazova State Farm. A total of 1549 lactation records of Simmental cows reared on Kazova State Farm between 1992 and 2002 were used. The factors for standardizing incomplete lactations to 305-day were estimated by taking 7 calving age groups into consideration insert ignore into journalissuearticles values(2, 3, 4, 5, 6-8, 9 and 10 years of age and older);. The factors for standardizing to mature equivalent estimated by polynomial regression are between the 24th and 143rd month and older. The repeatability of milk yield was estimated as 0.44 ± 0.028 using intra- class correlation. Heritability of milk yield was estimated using paternal half-sib correlation. Heritability of milk yield for all lactations was estimated as 0.24 ± 0.08. Heritability for first lactation was estimated as 0.30 ± 0.154.
Keywords : Simmental, milk yield, adjustment factors, repeatability, heritability